1. Field Of The Invention
The present invention relates generally to apparatus for handling containers holding liquid additives for use in the oil well service industry, and more particularly, but not by way of limitation, to such structures which are suitable for handling such containers on offshore vessels.
2 DESCRIPTION OF THE PRIOR ART
Many activities conducted in the oil well servicing industry require the use of liquid materials which have typically been provided in fifty-five-gallon drums. There is a substantial cost involved in the handling and disposal of such drums which typically are not reused.
The prior art also includes a number of liquid container systems designed for reuse. One recent development in such systems is that shown and described in U.S. Pat. No. 4,872,794 to Davis et al., and assigned to the assignee of the present invention. The Davis et al. apparatus describes a truck-mounted system providing a tank mounting apparatus for removably mounting reusable additive storage tanks on the truck. The truck-mounted system is of course only usable on land-based operations.
There is a need for a reusable container system which can be utilized on offshore oil well servicing operations. A complication in this goal is the requirement of various certifying agencies that structures carrying dangerous materials such as the additives which may be used in well servicing, meet certain stringent requirements for physical protection of those dangerous materials.
Previously the art has addressed this problem with tanks which each include an individual protective cage attached to the tank.
Another approach of the prior art has been to place drums in a closed freight container. After the closed freight container is placed on the offshore vessel, the tanks must then be removed from the container to load or unload additive materials from the tanks.